The publicly-known liquid dispenser normally has a liquid output member arranged at the center of a cover mounted at a container opening. A head cap is installed at the upper end of the liquid output member. Using the principle of air pump, i.e. applying a force by a user's hand to press the liquid output member, this publicly-known liquid dispenser makes the liquid in the container flow out via an outlet formed in the head cap. As a result, the user can use one of his palms to receive the liquid flowing out of the outlet while using the other palm to keep pressing the head cap so as to extract an appropriate amount of liquid contained in the container. However, at present the publicly-known liquid dispenser requires more parts to be built. The structure is complicated while not compact in construction. Furthermore, after the dispenser is assembled with the container, it cannot be used to output liquid in any direction because of its internal structure.